Síntese e caracterização de scaffolds do vidro bioativo 13-93 produzidos por processo freeze-casting para potencial aplicação em engenharia de tecidos ósseos

Abstract

Studies focused on synthetic materials for use in bone regeneration therapies is largely driven by the limitations observed in conventional treatments. Traditionally, bioactive glass (BG) has been used to fill and restore defects. More recently, this material gained significance in Bone Tissue Engineering. However, its performance as scaffolds is still insufficient because they lack the requisite balance between porosity and mechanical properties. Although beneficial to the mechanical properties of BG, a heat treatment step can lead to crystallization, which impairs its bioactivity. Consequently, it is necessary to study BG compositions less susceptible to this phenomenon. This work aimed to prepare scaffolds from 13-93 BG, a material with a chemical composition that favors sintering at lower temperatures and displays a low tendency to crystallize. This glass was prepared by the sol-gel process due to the inherent porosity and high purity of materials derived from it. The glass powder was then used to prepare scaffolds through the freeze-casting process. This technique allows preparing specimens with high control over the pore structure, which makes it suitable to produce scaffolds for Bone Tissue Engineering. The obtained materials were examined according to their particle size distribution, specific surface area, density, porosity, crystallinity, mechanical properties, and bioactivity. The results suggest that the sizes of the particles used in the freeze-casting process prevented the obtainment of a lamellar and oriented pore structure for the scaffolds. However, it was possible to sinter the scaffolds without the occurrence of crystallization, and the measured porosities were greater than 60 %, with a wide pore size distribution. The scaffolds showed Young's modulus values ranging from 1.10 to 1.40 GPa and compressive strength values varying between 12.7 and 22.4 MPa. Furthermore, the development of the HA layer after three days of immersion of the scaffolds in SBF confirmed the bioactivity of VB. The results presented in this study indicate the compatibility of these scaffolds with human trabecular bone and their potential application in Bone Tissue Engineering.